It is common practice to place eye-catching warning devices around a construction site or around a car broken down on the road as an effective alert to drivers and pedestrians passing by. In addition to bright orange traffic cones, some common examples of such warning devices are warning triangles, reflective plates, and reflective safety vests. Take warning triangles for instance. Commercially available warning triangles are provided with reflective plates for reflecting light projected from an approaching car. At night or dusk, however, the conventional warning triangles, which cannot emit light on their own, become less conspicuous and hence less effective in preventing accidents from happening.
As an improvement over the aforesaid prior art, warning devices capable of making sound or emitting light were developed. According to research and observation by the inventor of the present invention, these improved warning devices—be they warning triangles, traffic batons, or warning lights—are mostly powered by one-time batteries, though in some cases rechargeable batteries are used instead as the power source of light-emitting diodes or buzzers in the warning devices.
It is understood that the (stored) energy of a one-time battery or a rechargeable battery (hereinafter referred to collectively as a battery) will, by nature, be gradually released and lost. Therefore, a spare battery which has never been used will eventually lose at least some of its energy. If the batteries of a warning device happen to be dead or have insufficient electricity in case of an emergency, new batteries must be purchased, which not only costs extra money but also, when one-time batteries are used in large quantities, leads to a waste of resources and pollution, not to mention the untimeliness of the purchase, considering only the urgency of the situation. Moreover, it is practically impossible to buy new batteries if the emergency takes place in a mountainous area or a remote suburb or on the highway. Should attempts be made to charge the batteries of the warning device, the charging process is so time-consuming that the warning device may still be short of electricity and incapable of providing warning when needed; consequently, accidents may follow.
The issue to be addressed by the present invention is to solve the various problems of the conventional warning devices and provide a warning device with a fast energy storage element which can be fully charged within a short time. Thus, pollution as well as a waste of resources which may otherwise result from excessive use of one-time batteries can be prevented, and warning devices can be used in a more timely and convenient manner than the prior art counterparts.